Are there any built-in PHP functions or libraries that can help prevent multiple form submissions?

To prevent multiple form submissions, one common approach is to use a token-based system. When the form is submitted, a unique token is generated and stored in a session variable. This token is then included in the form as a hidden input field. When the form is submitted, the token is checked to ensure that it matches the one stored in the session, thus preventing multiple submissions. 

<?php
session_start();

// Generate a unique token
$token = md5(uniqid(rand(), true));

// Store the token in a session variable
$_SESSION['form_token'] = $token;
?>

<form method="post" action="process_form.php">
    <input type="hidden" name="form_token" value="<?php echo $token; ?>">
    <!-- other form fields -->
    <button type="submit">Submit</button>
</form>

Keywords

PHP form submission prevent duplicate token

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